The Qualification Round of the "CROC 2016" Championship will start on March, 16, 09:00 (UTC).

Please, read about the Championship by the link http://codeforces.net/blog/entry/43229

You need to participate in the Qualification Round to make it to Round 1. All contestants who gain a positive score will advance to the Round 1.

At the Qualification Round you will find a few problems, roughly ordered by the increasing complexity. During the Qualification Round the problems are judged only on pretests and system testing will take place after the end of the Qualification Round (round continues for 48 hours). The pretests do not cover all possible cases of input data, test your programs carefully! The Qualification Round has no hacks or decreasing values of the problems.

The round will last for 48 hours, but it does not mean that we encourage you to spend all this time solving of problems. We hope that most participants will cope with the problems (or with most problems) in a shorter period of time. This duration of the round is chosen so that each participant could find a convenient time to participate. The problems will be in English as well as in Russian.

Before the end of the round it is strictly forbidden to publish the problem statements/solutions/any thoughts and ideas about them elsewhere. It is forbidden to talk about the problems, discuss the statements and so on. Be honest and let the best participants make it into Round 1. When the Qualification Round is over, you can discuss the problems and solutions.

You can register for the round at any time up to its end.

The results of the round will not affect the rating. If you are not registered to the Championship officially, you can take part in the round out-of-championship.

Best of luck and enjoy solving the problems!

The final testing of VeeRoute Marathon is completed, the results are final. Congratulations to the winners!

I place, score: 488260.182 — Psyho

II place, score: 465947.075 — Rafbill

III place, score: 455743.464 — T1024

All of them will get their well-deserved reward. Additionally, by the organizer's decision, top 32 contestants will get a T-shirt: they are the contestants whose score is more than 300000. They represent 14 countries (Poland, France, Hungary, Belarus, Romania, Russia, Thailand, Lithuania, Hong Kong, Ukraine, Czech Republic, Sweden, Latvia and China) and used six different programming languages: C++, Java, Scala, Python, D and C#.

While the final testing took place, some of the contestants described their solutions:

• Psyho (1 place): greedy and two phases of simulated annealing;

• Rafbill (2 place): minimum cost bipartite matching: order chains and drivers;

• mugurelionut (7 place): graph on pairs (time, place) and greedy;

• LCM (19 place): greedy.

If you liked the marathon problem, we have good news: the second joint marathon is going to take place in two or three months. However, there's no reason to wait: if you are interested in a job at VeeRoute, fill the form, and the company representatives will contact you.

Speaking for myself, I'd like to thank the Codeforces platform and the company VeeRoute for the opportunity to conduct this contest.

The submission time is over for VeeRoute Marathon. Let us discuss the contest — the problem itself and related stuff — while the final testing takes place. Which solutions work best? Were the problem statement and materials sufficient to start solving, or something was lacking? What tools did you implement yourself?

Hi everybody!

Glad to tell you that tomorrow on 9:05 UTC there will be Codeforces Round #345. The round is formed of the first day of X Moscow Open Olympiad problemset with several additional problems created for this round. This round is brought to you by the scientific committee of Moscow Programming Olympiads controlled by GlebsHP, romanandreev and your humble servant, and also with a great help of fcspartakm who helped us make a complete problemset of our problems.

The round will be conducted under the standard Codeforces rules, you will be given 5 problems for 2 hours. Yes, this round is rated :)

Note that because of holding the main onsite round system testing and upsolving will be available no earlier than 12:35 UTC. Also we would like to ask you to not discuss problems in comments during the time between the end of the round and the end of the onsite competition. All comments with discussions will be removed and the most active violators will be punished. Thanks for your understanding.

UPD Sorry, the round start was moved to 9:25 UTC. It is not easy to run onsite round and Codeforces Round simultaneously!

UPD2 You may discuss the solutions! System testing will be run shortly.

UPD3 The editorial has finally appeared: http://codeforces.net/blog/entry/43677 Sorry for the delay!

Hello, Codeforces!

We are glad to invite all of you to test out our new Online Judge platform at csacademy.com. We're a Romanian based start-up that focuses on online education. Up until this point we've been working on creating a new environment for competitive programming contests.

Our first beta round took place in January and it was an IOI-style contest of medium difficulty. You can have fun solving the problems in our archive. Pay attention though, it is necessary to have an account in order to solve any problems on our website. You can connect via Facebook or Google+, or you can simply create a new account by providing a valid email address. Once you have an account you can choose a username, but all Codeforces handles are already reserved (so no tourist for the locals :D). We have created for you the possibility of connecting your Codeforces user here. Once connected, your Codeforces handle becomes available, otherwise it stays reserved for an indefinite amount of time.

Our second beta round will take place on Friday, Mar/04/2016 17:00 (UTC). If you want to take part in this round you need to register before the contest begins. Just like the previous round, the difficulty will be moderate (similar to a Codeforces Div. 2). You will have to solve 6 problems in 2 hours and 30 minutes.

This time around the format of the round will be different:

• There will be full feedback throughout the entire contest.
• Tasks will not have partial scoring, so you need to pass all test cases for a solution to count (ACM-ICPC-style).
• Tasks will have dynamic score. According to the number of users that solve a problem the score will vary between 100 and 1000.
• Besides the score, each user will also get a penalty that is going to be used as a tiebreaker. The penalty is computed taking into account the minute of the last accepted problem and the number of wrong submissions (only submissions for accepted tasks count).

More about our platform:

• For the best user experience we recommend using Google Chrome. We are still in beta and we didn't have time to check if everything works on other browsers.
• We currently support C++14, Java8, Python2 and Python3. We recommend using only C++ and Java for a contest, as the time limits are not calibrated for Python.
• We have a pretty cool online editor. We use it ourselves, so give it a try ;)

If you find any bugs please email us at [email protected]

People currently involved with CS Academy include:

• Mikester
• AndreiNet
• alex.velea
• Kira96
• gheorghemihai
• wefgef
• mihaic
• vladb

Don't forget to like us on Facebook, VK and follow us on Twitter.

EDIT: The editorial is ready. Congratulations to all the users and we hope you had a great time. Beta round 3 is around the corner, keep your fingers crossed!

EDIT2: We're hosting Beta Round #3.

Hello, Codeforces!

My name is Ivan Udovin, and I would like to say, that the Codeforces Round #344 will be held on Thursday (March 3, 2016 at 19:35). This is our first round, but it doesn’t mean that problems will be boring and not interesting. The problemsetters of this round are me (wilcot) and Ilya Kheifets (xfce8888). Thanks a lot to Alex Vistyazh (netman) and unknown person (he don’t want to be added in the announcement) for testing our round. Also I’d like to thank Fedor Korobeynikov (Mediocrity) for his awesome idea for task E.

We thank Gleb Evstropov (GlebsHP) for his help in preparing the contest, Maria Belova (Delinur) for translating the statements into English, and, of course, Codeforces team and Mike Mirzayanov for unique Codeforces and Polygon platforms.

This round consists of five problems. Main heroes of this round: Blake — the owner of the "Blake Technologies" company, and Chris — an employee of this company, and others.

Scoring distribution: 500, 1000, 1500, 2000, 2500.

Good luck, have fun.

PS. Editorial is ready.

PPS. Congratulations to the winners:

Div. 2:

1. lovelive

2. Murtazo.Ali

3. chychmek

4. chrome

5. Batman

Div. 1:

1. Um_nik

2. chffy

3. natsugiri

4. ershov.stanislav

5. AndreiNet

Hello, Codeforces!

Today is the first day of the spring and it's great!

Educational Codeforces Round 9 will take place on 01 march 2016 at 18:00 MSK for the first and the second divisions. You can read about educational rounds here and here. I should again notice the high density of contests and championships.

<This time it wasn't changed>

The round will be unrated for all users and it will be held with extented ACM ICPC rules. You will have two hours to solve six problems. After that you will have one day to hack any solution you want. You will have access to copy any solution and test it locally.

If you have ideas for some problems or maybe already prepared problems that you can't use in rounds or official competitions, you can write to me.

It seems that it is harder to invent interesting simple problems (like A and B) than difficult ones. So don't be afraid to suggest interesting simple or very simple tasks.

</This time it wasn't changed>

The problemset again was totally suggested by Codeforces users. The problem А again was suggested by user unprost (be ready to see a long problem statement). The problem D suggested by Denis Bezrukov pitfall. Alexey Chesnokov CleRIC sent the problem E a long ago. The problems B, C and F was suggested by Lewin Gan Lewin.

Thanks a lot to them and all others who are sending the problems or just ideas of the problems!

The problems was prepared by me (Edvard Davtyan). Thanks to Maria Belova Delinur for checking the English statements. The problems was tested by the same users who suggested them: unprost, Alexey Chesnokov CleRIC and Lewin Gan Lewin. Thanks a lot to all of them!

I hope you will enjoy the problems!

Good luck and have fun!

UPD1: The first part of the contest is finished. You can hack solutions.

UPD2: There are some technical problems. The phase of open hacks will be opened later (several hours).

UPD3: Editorial is ready.

UPD4: The contest is finished. We will start system testing in a few minutes.

UPD5: TOP3 of hackers:

P_Nyagolov — 31 hacks

khadaev — 27 hacks

halyavin — 23 hacks